Znd. Eng. Chem. Res. 1993,32,1245-1250
1245
Design Factors of Conical Spouted Beds and Jet Spouted Beds Martin 01azar,*Marfa J. San Jose, Andrbs T. Aguayo, Jose M. Arandes, a n d Javier Bilbao Departamento de Zngenierh Quimica, Uniuersidad del Pab Vasco, Apartado 644, 48080 Bilbao, Spain
Original aspects in the design of conical contactors used in spouting and jet spouting regimes have been studied. The experimental results correspond to different solids: glass spheres in the 0.0010.008-m particle diameter range, polystyrene, vegetable seeds, gravel, and Teflon, which have been used in contactors with different geometries (several angles and inlet diameters). The conditioning factors for instability of the spouted bed, which limit the maximum and minimum spoutable bed height, have been analyzed. A correlation has been proposed for the calculation of the minimum spoutable bed height as a function of the geometric factors of the contactor-particle system and density of the solid. From the bed hydrodynamics, correlations have been proposed to dimension the contactor as a function of the volume and properties of the solid to be treated in spouting and jet spouting regimes. 1. Introduction
2. Experimental Section
The regime of spouted bed in contactors of exclusively conical geometry has a special interest in gas-solid contact situations in which the use of conventional contactors, such as cylindrical ones and ones with a conical base, is not satisfactory. These situations happen in the treatment of solids that are adherent or have particle size distribution. In previous papers, the general conditions of stable operation of conical spouted beds, the design of the gas inlet (which greatly affects the operation stability) (San Jos6, 1991; Olazar et al., 1992), and the hydrodynamics (Kmiec, 1983;San Jos6et al., 1991,1992,1993;Olazaret al., 1992)have been studied. The expansion of conical spouted beds gives way to an original regime, the jet spouted bed (Markowski and Kaminski, 19831,whose stable operation conditions and hydrodynamic characteristics bring together advantages of both the conventional spouted bed and the contact regimes of high gas velocity (Olazar et al., 1992). The jet spouted bed, for which Epstein (1992) suggests the denomination “diluted-phase spouting”, has been successfully used in catalytic polymerization (Bilbao et al., 1987, 1989) and in coal gasification (Uemaki and Tsuji, 1986, 1991; Tsuji et al., 1989). When the spouted bed and jet spouted bed regimes in conical contactors are used in physical operations (drying, granulating, blending, coating, etc.) and in chemical reactions (combustion, gasification, pyrolysis, catalytic polymerization, etc.), design equations that facilitate dimensioning the operation at industrial scale are required. The obtaining of these design correlations from hydrodynamic correlations have the following as main difficulties for the spouting regime: (A) the difficult delimitation of stable operating conditions, which are more sensitive to the operating conditions than the spouting regime in cylindrical contactors; (B) the hydrodynamicpeculiarities attributable to the contactor geometry-no maximum spoutable bed height, except for stability limitations, and a minimum spoutable bed height, below which the upper surface of the bed is expected to fluidize. It must be pointed out that the jet spouting regime has no stability problems (Olazar et al., 1992). In this paper, the design equations of conical contactors for operation in the regimes of spouting (under stable operating conditions) and jet spouting are established. The hydrodynamic correlations previously obtained and a wide range of experimental results obtained at pilotplant scale have been taken as reference.
The equipmentused, the probesfor pressure and velocity measurement, their usage, and the general conditions for the experimental work have been detailed in a previous paper (Olazar et al., 1992). Five conical contactors of poly(methy1 methacrylate), whose geometric characteristics are defined in the diagram of Figure 1,have been used. They have been made to the following dimensions: column diameter, D,, 0.36 m; contactor base diameter, Di,0.06 m; heights of the conical section, H,, 0.36,0.40,0.45,0.50, and 0.60 m; cone angles, y, correspondingto the mentioned heights, 45,39,36,33, and 28’. With eachcontactor, the study has been extended to four inlet diameters, DO:0.03,0.04, 0.05, and 0.06 m. The solids used correspond basically to group D of Geldart (1973,1986)classification,for which these contact techniques can be especially interesting, and their properties are set out in Table I. The electrostatic charge problem of the extruded polystyrene bed was eliminated by treating the contactor surface with a commercial product of dimethylpolysiloxane. 3. Design Factors of Conical Spouted Beds 3.1. Maximum Spoutable Bed Height. Mathur and Gishler (1955) found for a cylindrical contactor that, for a given fluid and for particles of given diameter and density, there is a maximum spoutable bed height that may be treated in a stable spouting regime. For this maximum height, when the gas velocity is increased above that for minimum spouting, slugging is produced for large particles or aggregative fluidization for small particles (Becker, 1961; Reddy et al., 1968). Mathur and Epstein (1974) pointed out three mechanisms due to which the phenomenon of spouting becomes unstable from a given limit of height: 1,fluidization of solids in the upper surface of the annular zone; 2, choking of the spout; 3, propagation of the surface instability created at the base of the bed, which causes disappearance of the spout when this instability reaches a given bed height. For the calculation of the maximum spoutable bed height, empirical equations (Thorley et al., 1959; Malek and Lu, 1965) and equations deduced on theoretical bases (Littman et al., 1977,1979;Morgan and Littman, 1982; Morgan et al., 1988) have been proposed in the literature. In conical spouted beds there is no maximum spoutable bed height, at least not in the same way as is found in
0888-588519312632-1245$04.00/0 0 1993 American Chemical Society
1246 Ind. Eng. Chem. Res., Vol. 32, No. 6, 1993
solids, the maps corresponding to different contactors, gas inlet diameters, and particle diameters have been studied. From these maps, a general trend of the effect of each geometricfactor on the value of the maximum bed height cannot be established. Nevertheless, as general effects, the maximum spoutable bed height increases when the particle diameter decreases, when the Do/Di ratio decreases, and when the contactor angle increases. 3.2. Minimum Spoutable Bed Height. In conical spouted beds, the flow average velocity referred to the contactor diameter changes with height and, as a consequence, there is a minimum spoutable bed height, (H&, below which the velocity in the upper surface of the bed is higher than the minimum fluidization. This situation is one of the causes of instability detected experimentally under these conditions. In Table 11, the values of (H& experimentally observed for the different systems studied have been set out. The deduction of a theoretical correlation for the calculation of the minimum bed height has been approached by using the correlation deduced in a previous paper (Olazar et al., 1992) for the calculation of the minimum spouting velocity under stable operation conditions:
IC Figure 1. Geometric factors of the contactors. Table I. Promrties of the Solids Used ~~~
~~~~~
60
Geldart classification
0.322 0.328 0.345 0.355 0.361 0.378 0.405 0.449 0.412 0.446 0.490 0.507 0.395 0.395
B D D D D D D D D D D D D D
0.003 2800 0.70 0.410 0.0037 2180 0.80 0.452
D D
POI
material glass spheres
d,,m
k/ms
0.001 0.002 0.003 0.004 0.006 0.008 0.0096 beans 0.003 rice 0.0092 chickpeas 0.0068 Peas lentila 0.0044 expanded polystyrene 0.0035 extruded polystyrene 0.0035 polystyrene0.0035
polybutadiene gravel Teflon
6
1 1 1 1 1 1
2420 2420 2420 2420 2420 2420 1140 1250 1130 1110
0.65
0.60 0.90 0.70
1190 0.40 14 1 960 0.70 960 0.70
(Re,), = 0. 126ArO.' (DdD,)'*@[tan(7/2)1mi7 (1) Different equations for the calculation of the minimum fluidization velocity of large particles have been proposed in the literature (HBmati et al., 1991;Tannous et al., 1992). In this paper the equation of Thonglimp et al. (1984) has been used: Re, = (1.95 X 10-2)Aro*ss (2) This equation waa proposed for Archimedes numbers up to 70000 and has been used because this number's value is the highest found in the literature, although it is much lower than those corresponding to some of our experimental systems (Ar up to 4 X lo7). Combining eqs 2 and 1, both referred to the upper bed diameter, the following equation for the calculation of the minimum bed height to be treated, (H&, is deduced:
cylindrical contactors (Hadzismajlovic et al., 1986). Nevertheless, for large particles (glass spheres of greater than 0.005-m particle size) there is a maximum height due to instability of the spouting regime within a range of the contactor geometric factors. The cause of instability is clearly slugging that affects the whole section of the bed and whose formation does not have a direct relation to each contactor geometric factor (angle, inlet diameter) or to particle diameter, but it is a consequence of the three factors simultaneously. In a previous paper (Olazar et al., 1992),maps for stable operation obtained by experimental observation of the bed have been detailed. For different
In Figure 2, the values of (H& calculated using eq 3 for a contactor angle of 28O and for different values of particle
Table 11. Values of Minimum Stagnant Bed Heights, (Ha)= (Meters), for Different Solids and Particle Diameters and for Different Contactor Geometries Solid Glass Spheres 28O
330
36O
390
450
d,, m
d,, m
d,, m
d,, m
d,, m
D0.m 0.001 0.002 0.003 0.004 0.001 0.002 0.003 0.004 0.001 0.002 0.003 0.004 0.001 0.002 0.003 0.004 0.001 0.002 0.003 0.004 0.03 0.18 0.12 0.06 0.04 0.17 0.12 0.05 0.04 0.10 0.08 0.05 0.04 0.12 0.07 0.05 0.04 0.12 0.07 0.05 0.04 0.04 0.23 0.05 0.28
0.16 0.10 0.21 0.15
0.08 0.11
0.22 0.24
0.15 0.20
0.12 0.12
0.09 0.10
0.17 0.11 0.22 0.15
0.10 0.07 0.13 0.12 0.10 0.21
0.10 0.07 0.05 0.16 0.15 0.10 0.10 0.18
0.03 0.04 0.05 0.06
28 0.15 0.20 0.27 0.32
33 0.14 0.19 0.26 0.31
36 0.14 0.19 0.24 0.30
450 1.0
28O 2.6
39 0.14 0.18 0.23 0.29
45 0.14 0.18 0.22 0.27
28 0.08 0.10 0.13 0.16
33 0.07 0.10 0.12 0.15
Other Solids, DO= 6 cm peas chickpeas
rice
beans
28O 2.5
450 1.4
0.08 0.11
0.07 0.08
Solid: Teflon Y, deg
Solid Gravel 7 , deg DO,m
0.09 0.14
28' 2.5
450 1.0
28O 2.1
36 0.06 0.09 0.11 0.14
39 0.06 0.09 0.11 0.14
450 2.0
28O 2.5
lentila 450 1.5
28O 3.2
~~
45 0.06 0.08 0.10 0.13
polystyrene 450 2.0
Ind. Eng. Chem. Res., Vol. 32, No. 6,1993 1247
. 0 0
1.0
2.0
~
.
0
3.0 4.0 10' dp(m)
#
1.0
.
I
2.0
4.0
3.0
5.0
i o 3 dp(m)
Figun, 2. Experimental values (points) and those calculated using eq 3 (lines),of minimum spoutable bed height, for different particle diameters (glass spheres) and different contactor geometries.
diameter (glass spheres) are shown. Each curve corresponds to one value of inlet diameter. It is observed that the values of (Ho), calculated deviate from the values experimentally observed. A similar deviation is observed for the other contactor angles. The explanation of this deviation may lie in the fact that instability cannot be exclusively explained by fluidization of the upper surface of the bed. Summarizingthe experimentalobservations, instability has ita origin in phenomena associated with three designs factors, the Dold, ratio, the DdDo ratio, and the contactor angle, and with solid density. For high values of D d d , and low values of DdDo (near 11, big bubbles rise through the bed without spout formation, especially for the smaller particles (0,001 and 0.002 m) and for the smaller angles. On the other hand, the influence of the angle is not as sharp as that of the other two design factors. For solids of density lower than 1500 kg/m3 (beans, rice, chickpeas, peas, lentils, and polystyrene) the bed does not have any instability. For higher densities, there are instability phenomena depending on the value of the design factors previously pointed out. The (H& data of Table I1have been fitted by nonlinear regression to an equation with these dimensionless moduli that affect the bed stability:
0
-
0
1.0
The adequacy of eq 4 and its fitting to the experimental results is shown in Figure 3, where the values of (Ho), calculated using eq 4 (lines) and the experimental values for glass spheres set out in Table I1 (points) have been plotted vs the particle diameter. Each plot corresponds to one contactor angle. The resulta corresponding to 28, 36, and 45O have been plotted as examples. The effect of the parameters of the contactor-particle system can be analyzed in Figure 3. The values of minimum spoutable bed height increase in an exponential way as the particle diameter increases. They also increase
2.0
4.0
3.0
E 0
Figure 3. Experimental values (points) and those calculated using eq 4 (lines),of minium spoutable bed height, for different particle diameters (glass spheres) and different contactor geometries. t
A
kev solid gravel A teflon
Y .
0
0.25 I [tan(7/2)1 50.42
5.0
10' dp(m)
(Dddp)0.63[tan(y/2)l-o'.30 (4) The fitting has a regression coefficient of r2 = 0.85 and a standard deviation of 4% for the following range of the dimensionless moduli:
2.50 I (Ddd,) I 6 0
4.0
3.0
0
- p)/p)12.76(Di/Do)-o'47
1 I(Di/Do)I 3
2.0
10' dp(m)
a
@Io), = (1.41 X lO-")[(p,
1.0
10 102(
20
I
30
Ho),(m) experimental
Figure 4. Comparison of the values of minimum spoutable bed height calculatedusing eq 4 and the experimentalones for gravel and Teflon.
as the contactor inlet diameter decreases and, to a smaller degree, as the contactor angle decreases. In Figure 4, the fitting of ( H 0 ) m values calculated using eq 4 and the experimental values corresponding to other materials set out in Table I1(graveland Teflon) are shown. 3.3. Column Diameter. The diameter of the upper surface of the contactor, D,, is a parameter that can be designed at will to treat any volume of solid, as long as the key geometric factors for stability are maintained in the design (Olazar et al., 1992) and the remarks on trajectories of solid particles and bed pressure drop are taken into account (SanJose et al., 1992).
1248 Ind. Eng. Chem. Res., Vol. 32, No. 6, 1993 I
100,
0;
ioZH,(m)
Figure 5. Values of upper diameter of the contactor in spouting regime for different heights of stagnant bed height effect of contactor base diameter.
ob . i o
'
40
'
.so ' I30 1OZH,( rn)
'
IC0
Figure 6. Values of upper diameter of the contactor in spouting regime for different heights of stagnant bed height effect of contactor angle.
An equation for calculation of D, has been deduced from the relationships between the geometric factors of the contactors, the correlation of minimum spouting velocity, eq 1, and the correlation for bed expansion:
'
20
'
40
'
I30
'
eo
'
1'00
io2 H, (rn) Figure 7. Values of upper diametar of the contactor in spouting regime for different heights of stagnantbed height: effect of particle diameter.
stagnant bed height. The effect of the contactor base diameter is not very important, so the curves for different values of Di are almost parallel and very close to each other. In Figure 6, it is observed that the value of D, needed increases linearly with the value of bed height and more sharply as the angle is greater. The effect of particle diameter, Figure 7,is such that when this diameter decreases, the increase in D, with respect to bed height to be treated is sharper. The effect of particle diameter weakens when the value of this parameter increases. 4. Design Factors for Jet Spouted Beds
The jet spouted bed denomination corresponds originally to Markowski and Kaminski (1983), and its stable operation conditions and hydrodynamics have been studied in previous papers (San Josh, 1991;Olazar et al., 1992). (t - to)/(l- t) = 215(FD/FG)1'74(DdDO)1'35y1'95 (5) In short, the general characteristics of the jet spouted bed Equation 5 is valid for the regimes of spouting and jet are high gas velocity, high bed voidage (over 0.75 depending spouting. This equation has been calculated in a previous on the operating conditions), cyclic movement of the paper (San JosB et al., 1992) by taking into account the particles, hydrodynamic behavior different from that of which was introduced effect of the ratio of forces, FDIFG, the conventional spouted bed, and fewer instability by Kmiec (1977) and whose validity has been proven for problems than the spouted bed regime. particulate fluidized beds and conveyed beds (Kmiec, There is no maximum spoutable bed height in this 1982). regime as opposed to what happens in the spouting regime; From eqs 1 and 5 is obtained neither is there a minimum spoutable bed height as fluidization is a previous regime, which occurs for velocities D: = [Di + 2H0tan(y/2)I3(1+ +) - D!+ (6) much smaller than those for jet spouting. where Leaving aside the aspects already studied in previous rc,=rc,,= papers, which are related to the incidence of the geometric factors and to gas velocity on the trajectory of the solid Di+ W o tan(y/2) particles (San Jos6,1991) and on stability operativeness (8.94 x ~O')U:.~~AI--".~'[ DO (Olazar et al., 19921, there is no limit value for the bed diameter. Consequently, the bed can be set up with a value of upper diameter needed to treat any value of solid height. This value of diameter has been calculated from the relationship between the geometric factors of the contactor and from the following hydrodynamic correlations: for the calculation of the minimum jet In eq 7 the modulus has been expressed as a function spouting velocity of gas relative velocity, ur. In this way, eq 6 can be used in the contactor design for any gas velocity. (Re,), = 6.891Ar0~35(D~DO)1~48[tan(y/2)l-".63 (8) In Figures 5-7, the D, values calculated using eq 6 have and for the bed expansion, eq 5, which is also valid for the been plotted vs the stagnant bed height. The effect of the range of bed voidages corresponding to the jet spouted diameter of the contactor base (Figure 51, of the contactor bed regime (San Jose et al., 1992). angle (Figure 6), and of the particle diameter (Figure 7) The relationship deduced for the calculation of D, has has been analyzed. All of the results correspond to one the same expression as that for the conical spouted bed, value of contactor inlet diameter, DO= 0.04 m. eq 6, where J. as a function of gas relative velocity, ur,has As is observed in Figure 5, for the other constant the following value: geometric factors, D, increases almost linearly with
+
Ind. Eng. Chem. Res., Vol. 32, No. 6, 1993 1249 5. Conclusions dp=0.004m
01,
'
io
'
40
'
60
'
8'0
'
,bo
lozHo(m) Figure 8. Values of upper diameter of the contactor in jet spouting regime for different heights of stagnant bed height: effect of contactor base diameter.
tOeHo(m)
Figure 9. Values of upper diameter of the contactor in jet spouting regime for dfierent heights of stagnant bed height: effect of contactor angle.
0:
20
40 . 60 ' 8'0 ' loz H o b )
,bo
Figure 10. Values of upper diameter of the contactor in jet spouting regime for different heights of stagnant bed height: effect of particle diameter.
[tan(y/2)3-1.844y1s95
(9)
The effect of the geometricfactors of the contactor and of particle diameter on D, can be analyzed in Figures 8-10. In Figure 8, it is observed that the effect of the contactor base diameter is not very important and the results for different Divalues are very near to each other and parallel. For small values of bed height, when this height increases, D, increases but progressively in a less pronounced way, until the effect of HOcorresponds to a linear relationship. In Figure 9, the effect of Ho is the one previously pointed out. When the angle increases, D, increases, and this happens in a sharper way as HOincreases. When the particle diameter increases, the relationship D, vs Ho is affected to a great degree (Figure 10). The increase of D, with HOis smaller as the particle diameter is greater. Comparing this effect with that of the particle diameter for a spouted bed (Figure 7), the effect of particle diameter in the jet spouted bed is more important.
The spouted bed regime in conical contactors has maximum and minimum spoutable bed heights as limit design factors. These limit values are due to instability phenomenon caused by the formation of big bubbles and by slugging, which is observed in the whole bed section and whose formation is related to the contactor geometry and to the solid. The existence of a maximum spoutable height is experimentally observed for glass spheres of diameter greater than 0.006 m. Not only is the minimum spoutable height attributable to fluidization in the upper surface of the bed, but the instability created is also related to different design factors, that is to say, the Ddd, ratio, the DdDo ratio, and the contactor angle, and to solid density. The empirical relationship, eq 4, deduced to calculate the minimum spoutable bed height is valid in the whole range of operating conditions studied. Under stable operation conditions, the upper diameter of the conical contactor can be calculated using eqs 6 and 9. The jet spouting regime is stable in the whole range of operating conditions studied and does not have a minimum or maximum limit of bed height. The upper diameter of the cone can be calculated using eqs 6 and 10.
Nomenclature
Ar = Archimedes number, g d s ( p , -
p)/p2
CD = drag coefficient, (24/Re)(l + OS l.ReO@ . )' Db,D,,Di,DO= top diameter of the stagnant bed, of the column (or upper diameter needed for the cone),of the bed bottom, and of the bed inlet, respectively, m d, = particle diameter, m F D / F ~= ratio between drag and gravitational forces, V4CDRe2/Ar H,,HO= height of the conical section and of the stagnated bed, m (H& = minimum spoutable bed height, m Red = Reynolds number of minimum fluidization,pu&,Jp (Reo)d,(Re&, = Reynolds number of minimum jet spouting and of minimum spouting, referred to DO u, urn = gas velocity and gas velocity of minimum spouting referred to Di,m 8-l u d = gas velocity of minimum fluidization, m 8-1 u, = gas relative velocity, u/u, Greek Letters to, t = voidage of stagnant bed and of bed y = cone angle, radians p = viscosity, kg m-1 8-1 p, ps = density of the gas and particle density, kg m-S 4 = particle shape factor, surface area of equivolume sphere/ surface area of particle
Literature Cited Becker, H. A. An Investigation of L a w Governing the Spouting of Coarse Particles. Chem. Eng. Sci. 1961,13, 246262. Bilbao, J.; Olazar, M.; Romero, A.; Arandes, J. M. Design and Operation of a Jet Spouted Bed Reactor with Continuous Catalyst Feed in the Benzyl Alcohol Polymerization. Znd. Eng. Chem. Res. 1987,26, 1297-1304. Bilbao, J.; Olazar, M.; Romero, A.; Arandes, J. M. Optimization of the Operation in a Reactor with Continuous Catalyst Circulation in the Gaseous Benzyl Alcohol Polymerization. Chem. Eng. Commun. 1989, 75, 121-134. Epstein, N. Introduction and Overview. Can. J. Chem. Eng. 1992, 70,833434,839. Geldart, D.Types of Gas Fluidization. Powder Technol. 1971, 7, 286292. Geldart, D.Gas Fluidization Technology; Wiley: New York, 1986.
1250 Ind. Eng. Chem. Res., Vol. 32, No.6, 1993 Hadzismajlovic, Dz. E.; Grbavcic, Z. B.; Vukovic, D. V.; Povrenovic, D. S.; Littman, H. A Model for Calculating the Minimum Fluid Flowrate and Pressure Drop in a Conical Spouted Bed. In Fluidization V; Ostergaard, K., Sorensen, A., Eds.; Engineering Foundation: New York, 1986; pp 241-248. HBmati, M.; Steinmetz, D.; Laguerie, C. Coarse Particle Fluidization: Velocities and Porosities of Minimum Fluidization. In Recents Progrbs en Genie desProcBdb. Vol.5. La Fluidisation; Laguerie, C., Guigon, P., Eds.; Lavoisier-Technique e t Documentation: Paris, 1991; pp 39-46. Kmiec, A. Expansion of Solid-Gas Spouted Beds. Chem. Eng. J. 1977,13, 143-147.
Kmiec, A. Equilibrium of Forces in a Fluidized Bed-Experimental Verification. Chem. Eng. J. 1982,23,133-136. Kmiec, A. The Minimum Spouting Velocity in Conical Beds. Can. J. Chem. Eng. 1983,61,274-280. Littman, H.; Morgan, M. H., III; Vukovic, D. V.; Zdanski, F. K.; Grbavcic, Z.B. A Theory for Predicting the Maximum Spoutable Height in a Spouted Bed. Can. J. Chem. Eng. 1977,55,497-501. Littman, H.; Morgan, M. H., 111; Vukovlc, D. V.; Zdanski,F. K.; Grbavcic, Z. B. Prediction of the Maximum Spoutable Height and Average Spout to Inlet Tube Diameter Ratio in Spouted Beds of Spherical Particles. Can. J. Chem. Eng. 1979,57,684-687. Malek, M. A.; Lu, B. C. Y. Pressure Drop and Spoutable Bed Height in Spouted Beds. Znd. Eng. Chem. Process Des. Dev. 1965, 4, 123-128.
Markowski, A,; Kaminski, W. Hydrodynamic Characteristics of Jet Spouted Beds. Can. J. Chem. Eng. 1983,61,377-381. Mathur, K. B.; Epstein, N. Spouted Beds; Academic Press: New York, 1974. Mathur, K. B.; Gishler, P. E. A Study of the Application ofthe Spoutad Bed Technique to Wheat Drying. J. Appl. Chem. 1955,5,624636.
Morgan,M. H., 11%Littman, H. Predicting the Maximum Spoutable Height in Spouted Beds of Irregularly Shaped Particles. Znd. Eng. Chem. Fundam. 1982,21, 23-26. Morgan, M. H., III; Littman, H.; Sastri, B. Jet Penetration and Pressure Drops in Water Spouted Beds of Fine Particles. Can. J. Chem. Eng. 1988,66,735-739. Olazar, M.; San Josh, M. J.; Aguayo, A. T.; Arandes, J. M.; Bilbao, J. Stable Operation Conditions for Gas-Solid Contact Regimes in Conical Spouted Beds. Znd. Eng. Chem. Res. 1992, 31, 17841792.
Reddy, K. V. S.; Fleming, R. J.; Smith, J. Maximum Spoutable Bed Depths of Mixed Particle-Sized Beds. Can. J. Chem. Eng. 1968, 46,329-334.
San JoaB, M. J. OperationRegimes in Conical Spouted Beds. Stability Conditions and Hydrodynamics. Ph.D. Dissertation, University of the Basque Country, Bilbao, Spain, 1991. San JoaB, M. J.; Olazar, M.; Aguayo, A. T.; Arandea, J. M.; Bilbao, J. Design and Hydrodynamics of Conical Jet Spouted Beds. In Recents Progres en Genie des Prockdes. Vol. 5. La Fluidisation; Laguerie, C.; Guigon, P., Eds.; Lavoisier-Technique e t Documentation: Paris, 1991; pp 146-153. San Jos6, M. J.; Olazar, M.; Aguayo, A. T.; Arandes, J. M.; Bilbao, J. Hydrodynamic Correlations of Conical Jet Spouted Beds. In Fluidization VZI; Potter, 0.E., Nicklin, D. J., Eds.; Engineering Foundation: New York, 1992, pp 831-838. San JoeB, M. J.; Olazar, M.; Aguayo, A. T.; Arandes, J. M.; Bilbao, J. Expansion of Spouted Beds in Conical Contactors. Chem. Eng. J. 1993, 51, 45-52. Tannous, K.; HBmati, M.; Laguerie, C. Coarse Particle Fluidization. Velocity and Voidage of Minimum Fluidization and Bed Expansion. In Fluidization and Fluid Particle Systems ZI; Bilbao, R., Adhez, J., Eds.; University of Zaragoza, CSIC: Zaragoza, Spain, 1992; pp 41-48. Thonglimp, V.; Hiquily, N.; Laguerie, C. Minimum Fluidization Velocity and Expansion of Gas Fluidized Beds. Powder Technol. 1984,38, 233-253.
Thorley, B.; Saunby, J. B.; Mathur, K. B.; Osberg, G. L. An Analysis of Air and Solids Flow in a Spouted Wheat Bed. Can. J. Chern. Eng. 1959,37, 184-192. Tsuji, T.; Shibata, T.; Yamaguchi, K.; Uemaki, 0. Mathematical Modelling of Spouted Bed Coal Gasification. Proceedings of the International Conference on Coal Science; The Society of Chemical Engineers: Tokyo, 1989; Vol. I, pp 457-460. Uemaki, 0.; Tsuji, T. Gasification of a Sub-Bituminous Coal in a Two-Stage Jet Spouted Bed Reactor. In Fluidization V; Ostergaard, K., Sorensen,A., Eds.; EngineeringFoundation: New York, 1986; pp 497-504. Uemaki, 0.; Tsuji, T. Coal Gasification in a Jet Spouted Bed. Roceedings of the 41st Canadian Chemical Engineering Conference; CSChE Publications Department: Ottawa, Ontario, 1991; NO 17-1. Received for review October 14, 1992 Revised manuscript received March 1, 1993 Accepted March 16,1993
